1. Field of the Invention
The present invention relates to a roll feed apparatus used to feed plates intermittently to an industrial machine such as a press.
2. Description of the Prior Art
Japanese Utility Model Laid-Open No. 61-32150 (Utility Model Application No. 59-114306) discloses a roll feed apparatus which includes: first and second rolls fixed to first and second roll shafts, respectively, the rolls being adapted to grip a plate and thereby convey it when they are rotated in first directions and being moved away from each other so as to loosen the grip when rotated in second or opposite directions; and first and second brake pieces disposed on both sides of a plate passageway in such a manner as to face each other, for fixing the plate when the two rolls are rotated in the second directions. In the roll feed apparatus of this type, in order to increase the accuracy with which the plate is conveyed without sliding, it is necessary that the gap between the two rolls is suitably adjusted in accordance with the thickness of the plate. When the plate to be conveyed has a thickness which changes in the lateral direction, it is desirable to change the gap between the two rolls in the axial direction thereof to cope with the change in thickness of the plate in the lateral direction. In the above-described known roll feed apparatus, these objects are attained by the provision of a first roll shaft whose both ends are rotatably mounted in a housing with eccentric flanges therebetween. Rotation of the eccentric flanges moves, together with the first roll shaft, the two ends of the first roll toward or away from the second roll.
The known apparatus, however, suffers from problems in that the rotation of the eccentric flanges requires the time-consuming process of removing a cover and unscrewing bolts, because the eccentric flanges are fixed to the housing by bolts and because they are covered with the cover, and that the operation of the roll feed apparatus must be stopped during this process. Further, since the eccentric flanges are tightly fitted to the first roll shaft and the housing, they must be hit by a hammer to make them rotate, making the rotation of the flanges time-consuming and making fine adjustment of the gap between the two rolls difficult.